1. Field of Invention
The present invention is related to a method for eluting antimony, which has been adsorbed on the chelating resin, thereby separating antimony from the chelating resin and hence recovering antimony. More particularly, the present invention is related to a purification method of an antimony-containing electrolyte from the copper refining process and the like, so as to recover the antimony from such electrolyte.
2. Description of Related Art
In the copper refining process, in which the electrolyte is subjected to deposition of copper, antimony is left in the electrolyte and is then removed from the electrolyte by, for example, ion-exchanging using a chelating resin, a functional group of which is aminophosphonic acid.
A method for removal and recovery of antimony from the chelating resin, is illustrated in the flow chart shown in FIG. 1 with the following reference numerals: 1--concentrated hydrochloric acid tank; 2--acid-conditioning tank; 3--acid feed-tank; 4--chelating-resin tower; 4a--chelating resin; 5--neutralizing tank; and, 6--filter press.
The concentrated hydrochloric acid from tank 1 and the liquor from the chelating resin tower 4, described in detail hereinafter, are mixed in the acid-conditioning tank 2, where the HCl concentration is adjusted to approximately 6N (c.f. 4). The hydrochloric acid solution with adjusted concentration is then once stored in the acid feed-tank 3 and is then passed through the chelating-resin tower 4. The hydrochloric acid, as eluting solution, is caused to react with the chelating resin 4a, on which the antimony has been adsorbed. The antimony is thus eluted in the form of SbCl.sub.3 (c.f. 2). The eluted antimony is brought into contact with an alkali such as Ca(OH).sub.2 in the neutralizing tank 5 to convert SbCl.sub.3 to Sb(OH).sub.3, which is then subjected to the filter press 6 (c.f. 3).
Referring to FIG. 2, the relationship between the eluting time and the antimony concentration of the eluate is shown. As is shown in FIG. 2, most of the antimony is eluted from the chelating-resin tower 4 at the initial eluting stage. The eluate with high Sb-concentration yielded in the initial eluting period is transferred to and neutralized in the neutralizing tank 5 and is then subjected to the recovery stage of Sb(OH).sub.3. Meanwhile, the eluate with low Sb-concentration yielded in the subsequent period is not neutralized but is transferred into the acid-conditioning tank 2 and is mixed with concentrated hydrochloric acid. The resultant mixture is re-used as the eluting acidic solution, as described above. The initial and subsequent eluting treatments are carried out, as described above, while leaving some portion of the eluate in the chelating-resin tower 4. This remaining eluate is air-purged and, then, the chelating resin 4a is scrubbed or washed with water. The air-purged and hence removed eluate and a portion of the scrubbing water are recovered to re-use for the acid-conditioning. The other portion of the scrubbing water is exhausted as waste liquor outside the liquor purification system shown in FIG. 1.